The present invention concerns a seat-belt system, especially for use in motor vehicles although not limited to that field of application. One end of the belt is secured to the vehicle or in a belt tensioner. A buckle engages with a belt-locking mechanism that is fastened to the vehicle. A mechanism that can be employed when desired to sever the belt is clasped tight against one section of the belt. The belt-severing mechanism includes a slot that accommodates the belt. One section of the slot clasps at least one section of the belt as the belt extends through it.
Seat-belt systems of this type and for this purpose are generally known. Millions of what are called three-point belts have already been employed, especially in motor vehicles. One end of the belt is accommodated on a belt tensioner that locks the belt in place when the vehicle sudden decelerates. The other end of the belt can be secured for example to the bottom of a post between the vehicle's front and rear doors. A buckle travels back and forth along the belt and can engage a belt-locking mechanism.
Although seat-belt systems of this type have often been proven effective, they do have drawbacks. They can for example prevent passengers from getting out of a vehicle that has been badly damaged in an accident. Mechanisms clasped tight to sections of the belt and severing them in such emergencies have accordingly been suggested.
A seat-belt severing device for motor vehicles is known from German OS 2 841 404 for example. It comprises a belt-accommodating slot between a base and a top. A blade extends across a belt that extends through the slot. The belt-accommodating slot has a section on one side of the blade guide that clasp at least one section of the belt tight when the system is in use and prevents the device from undesirably sliding along the belt.
A device similar in structure and purpose and called a belt capper is known from German GM 8 223 436. The belt-accommodating slot also has a clasping section on one side of the blade guide, whereas the section of the belt-accommodating slot on the other side of the blade guide only loosely secures the section of belt that extends through it.
The severing-mechanism clasping sections of the belt-accommodating slots ensures that these known belt-severing mechanisms will not slide back and forth along the belt. The mechanisms can accordingly be simply mounted at preferably accessible points on the belts. It is recommended that the section of a buckled motor-vehicle seat belt between the end secured to the vehicle and the buckle be on approximately the same level as the thighs of the passenger that the belt is securing.
Since the belt-severing mechanism cannot slide back and forth along the belt because of being clasped tight within a section on one side of the blade guide, the mechanism must be mounted on the belt with the severing-mechanism clasping section facing the end of the belt secured to the vehicle so that, when the belt is severed, the section on the other side of the blade guide can slide unimpeded out of the belt-accommodating slot. If on the other hand the belt-severing mechanism is incorrectly secured to the belt with the severing-mechanism clasping section toward the buckle, only the section of the belt that is fastened to the vehicle will be able to slide out of the belt-accommodating slot, and the belt-severing mechanism, which is clasped tight in the clasping section, will remain fastened to the other section of the belt. The severed belt can accordingly slide through the buckle only until the belt-severing mechanism comes into contact with the buckle and will not release the passenger secured by the belt.
The known belt-severing mechanisms have also been proven difficult to handle in that the blades, which are accommodated in transverse guides, can only be actuated by removing means of security that act at an angle to, and interlock with, the blade guides and applying tension to eyes that project out next to the severing mechanism. It has been demonstrated that such means of security are difficult to disengage when a vehicle is severely damaged and that it is accordingly difficult to rescue accident victims. Since vehicular collisions always entail a risk of fire however, getting the passengers out on time is a matter of life or death.